Closed breech rocket gun



Jan. 4, 1966 G. R. KRuzELL CLOSED BREECH ROCKET GUN 2 Sheets-Sheet 1Filed July l5, 1964 lNvrm'roRI 650,665?, Kef/25a ATTORNEYS m \\\\\\mm\\\\\\\\\\\\\mmmnnhhn nnn/d lll l m l l n N S \\\J .ll nl' i I ll.\\\\\\\\\\\\\\\\\\\\\\w\\\\\\ fue f of BY mm, mymzgfww Jan. 4, 1966 G.R. KRUZELL CLOSED BREECH ROCKET GUN 2 Sheets-Sheet 2 Filed July l5, 1964BY www, Mmz WM f F mw om rm Aom mm ch Nm ATTORNEYS I United StatesPatent O 3,227,045 CLOSED BREECH ROCKET GUN George R. Kruzell, 4301Hotchkiss, Bay City, Mich. Filed July 15, 1964, Ser. No. 382,863 9Claims. (Cl. 89-187) Closed breech rocket guns or launchers haveheretofore been known and used, having possessed the well-knownadvantage of preventing the backward discharge of propellant gases andthereby permitting use of such guns as shoulder weapons or in gunturrets or tanks without danger of injury to the gunner or others in therear of the gun. In addition such closed breech guns have permitted anincreased range by virtue of the thrust-assist exerted upon the rocketby the rearwardly discharged gases.

In order to achieve their function it is obvious that the breech closingmechanism of such a gun must be extremely eflicient and reliable inoperation and capable of eifecting a gas tight closure of the breech toavoid the dangerous rearward discharge of gases. In order for such abreech closing mechanism to function properly and reliably, it has beenheretofore necessary to employ positive locking mechanism formaintaining the breech closing mechanism in its closed and sealingposition, with the consequent necessity of releasing such lockingmechanism each time a fresh round is delivered into the firing chamber.

In View of these considerations previous breech closing mechanisms forclosed breech rocket guns or launchers have not been altogethersatisfactory, but in general have been so slow and cumbersome in theiroperation as to be applicable only to weapons of a single shot orsemiautomatic type rather than to those which are capable of automaticfiring.

The present invention has been developed with these considerations inmind and has for its primary object the provision of a fully automaticclosed breech type rocket gun in which the breech locking mechanism isreliably actuated and released in accurately timed relation to theautomatic firing of the weapon. v

The locking mechanism is arranged to maintain the breech closure in itsclosed and sealed position during the peak gas pressures existing withinthe gun barrel and ring chamber during the firing of each round, and toautomatically release the breech closure as each round leaves the gunbarrel. The invention contemplates the use of a release mechanism forthe locking means which is actuated by gas pressure created within thegun barrel incident to firing of the gun, such pressure being bled offthrough a port which is so located along the length of the barrel as toactuate the release mechanism in properly timed relation to the firingoperation.

It is a further object to provide such a gun which is also selectivelycapable of firing either as a single shot weapon or as a semiautomaticweapon.

Further objects are to provide such a gun involving a minimum number ofsimplified assemblage of parts.

In order to illustrate the best mode presently known to me of carryingout the invention, there is illustrated in the accompanying drawings thepreferred embodiment of the invention. It is to be understood that thesedrawings and the detailed description hereinafter following areexemplary only and will involve details which may be omitted or changedas will be apparent to those skilled in the art, without departing fromthe invention.

In the accompanying drawings:

FIGURE 1 is a View, partly in vertical section and partly in elevation,of a rocket gun embodying the invention, a portion only of the gun stockbeing shown;

FIGURE 2 is an enlarged fragmentary section through ice the gun barrel,taken on the same plane as FIGURE l, and showing certain parts in brokenlines in their actuated positions;

`FIGURE 3 is an enlarged vertical section through the receiver andfiring chamber of the gun, showing the bolt locked in its operativeposition, with the gun loaded, cocked and in readiness for ring, thefiring pin being illustrated in broken lines in the projected positionwhich it assumes incident to firing the gun;

FIGURE 4 is a View similar to FIGURE 3, showing the parts in theretracted positions immediately after ring and midway of the automaticreloading cocking operation; and

FIGURE 5 is an enlarged cross section through the gun barrel, on theline 5-5 of FIGURE 1.

FIGURE 6 is a detail sectional view ontthe line 6 6 of FIGURE 4illustrating the relative widths of the bolt locking recess and thesear, both the bolt and the sear being shown but fragmentarily.

Referring now in detail to the accompanying drawings:

The automatically ring closed breech rocket gun therein illustrated isof comparatively small size, to be capable of use in the manner of ashoulder gun or hand weapon. To this end it is provided with a usual gunstock 10 which may conveniently be of wood, plastic or otherconventional materials and which is rigidly connected in a generallyconventional manner to the rear end of the receiver 11. There may alsobe provided a usual supplemental support in the form of a pistol grip 12firmly affixed to the receiver 11, as by means of the screws 13. It willbe understood of course that Where the gun is formed in larger sizes itmay be provided with suitable gun mounts of conventional nature in lieuof the stock 10 and pistol grip 12.

In the embodiment here illustrated, it will be seen that the stock 10includes an adapter piece 14 rigidly ailixed thereto at its forward end.A portion 15 of'the adapter projects into and is snugly received withinthe rearwardly opening end of the hollow receiver 11 to function jointlyas a closure plug and support. A screw 16 threaded transversely throughthis plug 15 and the receiver end, firmly secures these parts inassembled relation. If desired, a reinforcing rod 17 extendinglongitudinally through the stock may be threaded into the adapter piece14 at its inner end 18 as shown. 3

Axed to the forward end of the receiver is a preferably internallyrifled gun barrel 20 having a ring chamber 21 which communicatesrearwardly withv the forwardly opening end of the hollowtreceiverthrough a breech opening 22, withv the bolt well 23 of the receiver. Thebarrel 20 may be rigidly connected to the receiver in generallyconventional manner as by shrink fitting its rear end into a counterbore24 in the forward end of the receiver.

As is well-known, the firing of a rocket type projectile or missilewithin the barrel 20 will result in the creation of an internal gaspressure which greatly exceeds that occurring within the barrel of amore conventional'rearm. It is therefore desirable to release asubstantial portion of this pressure in order to avoid explosion of thebarrel. This pressure release may be accomplished in conventional mannerby provision in the barrel, adjacent the forward end of the firingchamber, of one or more gas release ports 25 which are normally coveredand closed by the missile or projectile P when operatively positionedwithin the firing chamber, but which are un-y covered promptly upon theinitiation of forward move# are released through these ports 25, it isvdesirable to,y

provide a blast jacket 26, which is 'here shown vas a forwardf extensionof the receiver. This jacket 26 encircles and is spaced radially fromthe barrel and is preferably coextensive in length therewith, -to definea forwardly opening blast pressure relief passage 27 around the barrel.Since the rear end of this passage 27 is closed by the receiver, asshown, the gases which emerge through the release ports 25 will bedirected forwardly away from the gunner, An advantage of this specificarrangement is that the released gases which thus emerge from theannular passage 27 assume the form of a sheath surrounding therearwardly directed.

gas blast from the rocket or missile P as the latter emerges from thebarrel, thereby functioning as a shield for the gunner.

The bolt well 23 will normally be of uniform cross sectional shape anddimensions throughout its length, except that at its forward end it isprovided with a forwardly converging generally conical sealing surface28 just rearwardly of the breech opening or constriction 22.

In the present embodiment, the breech closure is illustrated as in theform of a bolt 30 of a cross sectional shape (preferably cylindrical)and dimension throughout the major portion of its length correspondingto those of the bolt well. The bolt 30 is guided within the weil forlongitudinal Vsliding movement between its forwardly projected breechclosing and sealing or firing position, as shown in full lines inFIGURES 1 and 3, and its fully retracted position as shown in FIGURE 4.At its forward end, the bolt 31B is provided with a forwardly convergingconical sealing surface 31 tapered at an angle similar to that of thesealing surface 28, so that in the forwardly projected position of thebolt these interengaged sealin'fr surfaces 28 and 31 provide a gas tightseal rearwardly of the firing chamber and breech opening 21 and 22,respectively, to prevent rearward escape of gases incident to the firingof the weapon.

For urging the bolt forwardly to its fully projected breech closing andsealing position, there are provided suitable resilient means, asexemplified by the bolt return spring 32 compressed between the bolt andthe closed rear end or plug of the receiver and maintained in alignmentby reception of one end thereof in a blind bore 33 opening rearwardlythrough the end of the bolt, and the guide rod 34 supported from theplug portion 15 of the adapter piece 14.

In order to provide a convenient means for manually retracting the bolt30 against the spring 32, the bolt may be provided with a rigidlycarried operating handle ,'55 projecting outwardly and movable through alongitudinally extending narrow slot 36 in the receiver wall.

Carried by the bolt for longitudinal movement therein is a firing pin 38which includes a forwardly projecting striker of general conventionalnature snugly slidably disposed through a longitudinal or axial passagein the bolt for forward projection into operative firing engagement withthe primer or igniter lof the projectile P a firing pin spring 39tensioned between the bolt 30 and firing pin 38 serve to project thefiring pin forwardly from its retracted or cocked position to its firingposition as shown in full lines in FIGURE l.

To provide for cocking the firing pin, the rear end of the latter isformed with a cooking detent 40 for cooperation with the sear 41.

Sear 41 is guided on the receiver for projection movement into the boltwell 23, transversely to the movement of the bolt and across the path ofmovement of the firing pin cocking detent 40, for holding abutmenttherewith to cock the firing pin incident to return or forward movementof the bolt from its retracted position.

In the instant embodiment, the sear 41 is slidably guided throughopenings in the wall of the receiver 11 and in a bracket 42 aixedthereto, and is resiliently projected into the receiver well by the searspring 43.

Spring 43 is compressed between the sear and an abutment 44 carried bythe receiver, the major portion of the spring preferably being housedwithin a recess 45 in the sear.

For permitting retraction of the bolt and firing pin past the normallyinwardly projected sear 41, the latter is provided with a forwardlypresented inclined cam surface 41 to cause retraction of the searincident to its successive engagement with the rearwardly directed andpreferably similarly inclined cam surfaces 40 and 315 of the firing pincocking detent 050 and the bolt 30 respectively. It will be apparentthat during the forward return or projection movement of the bolt fromits retracted position, the tapered sealing surface 31 of the bolt willengage and exert a camming action of the sear 41 to cam the latter outof the path of travel of the bolt. The sear 41 will have sufcient widthtransversely of the bolt and receiver to span the relatively narrowerlocking recess 46 adjacent the forward end of the bolt.

The trigger or trigger means 47, by which the sear 411 is selectivelydisengaged from the iiring pin to permit forward spring projection ofthe latter into operative actuating engagement with the primer of themissile to be fired, is shown in the present embodiment as beingmedially pivotally mounted at 50 on the receiver and normally urged byits spring 51 in a counterclockwise direction as seen in FIGURE l. Theforwardly projecting lever arm 52 of the trigger is formed with aforwardly opening 1oore 53 which receives and guides a disconnector orlug 54. This lug is normally spring projected forwardly from the leverarm 52 for operative engagement with a laterally rearwardly extendinglug on the sear. The free end of the disconnector 54, when fullyprojected, is so spaced from the trigger pivot E@ that when the triggeris pulled rearwardly with ensuing downward swinging movement of itslever arm 52, the disconnector 54 will remain in abutting engagementwith the lug 55 until such time as the seat has been fully retracted torelease the ring pin 37.

The arc of movement of the disconnector free end is such however withrespect to the straight line movement of the sear that the disconnector54 will ride free of and disengage the lug 55 after the sear is thusfully retracted. In other words this arrangement provides forautomatically disconnecting the trigger from the sear after the sear hasbeen retracted to release the firing pin, whereby the scar may be freeto immediately return to its operative position without interferencefrom the trigger, even though the latter be maintained in its firingposition. This insures return of the sear to operative position so thatimmediately after the firing of a round and the resulting rearwardrecoil and return of the bolt 30 as hereinafter described, the sear 41will be operatively positioned for engagement with the ring pin cockingdetent 40 to cock the firing pin as the bolt is projected by spring 32to its forward breech sealing position.

In order to permit return of the trigger to operative posi-tion withoutblockage by the sear lug 55, the latter is formed with an upwardly andrearwardly inclined cam surface 55 for retraction of the disconnector topermit the disconnector 54 and its associated lever arm 52 to ridefreely therepast, as the trigger returns to operative position. A stop56 carried by the lower end of the sear 41 abut's against the sear guidebracket 42 to limit the upward projection movement of the scar.

Opening into the receiver 11, in la position generally abreast of thebolt 3% in its breech closing position, is a loading port 57 throughwhich ammunition is automatically inserted in front of the retractedbolt 30 by a conventional magazine 58. In accordance with usualpractice, the magazine includes a magazine 'spring 6) compressed betweenthe magazine bottom and a follower 61 to urge each of a plurality ofrounds of ammunition P locking lug or bolt lock 65.

upwardly successively through the loading port 57 and into the receiverin advance of the bolt, whenever the latter is retracted from itsblocking position over the loading -port 57.

' The ammunition P, shown for purposes of exemplification, comprises aplurali-ty of individual rounds -or shells, each comprising a cartridgecase 62 which will be understood to contain a booster charge of powderor other explosive and a primer or ignitor 63 centered at the vrear endof the casing 62 in position for operative engagement 'by the forwardend of the tiring pin striker 38. In the instant embodiment it isintended that the cartridge case 62 remain stationary in the firingchamber when a missile is rst tired, to ignite .the propellent chargewithin the missile or projectile P, as well a-s to initiate the forwardm-ovement of the latter. It will be understood that any usual relcasableconnection may be employed between the cartridge 62 and the projectileP.

i As the missile or projectile P leaves the forward end of the barrel20, the gas pressure within the barrel is relied upon to force both theplunger 30 Iand the expended cartri-dge 62 rearwardly into the receiversu-ch that the cartridge case 62, upon arriving at a location abreast ofthe ejector port 64 is kicked outwardly through said port by aconventional ejector mechanism. The ejector mechanism may be of a purelyconventional lever type, actuated by movement of the bolt, and due toits conventional nature is not here specifically illustrated.

It is important that, during the firing of each missile, the bolt 30shall be firmly retained in its forwardly projected breech sealingposition, with its -conical sealing surface 31 engaged in gas tightmann-er with the relatively opposed sealing surface 28 of the receiver,to thereby prevent the rearward escape of gases which might injure thegunner or others in his vicinity, or which might corrode or coat thesealing surfaces 28, 31 in a manner to impair their sealing function.

For achieving these ends, the bolt is provided with the bolt lockingrecess 46, earlier referred to, having a rearwardly presented lockingface 46' for operative abutting engagement with the cooperating lockingface 65 of Ia The lock 65 is guided in a housing 66 on the receiver forrectilinear sliding movement transversely to the bolt movement into andfrom the locking recess 46 of the bolt. Spring means 67, compressedbetween the locking lug 65 and the end plate 68 of the housing 66 servesto resiliently project the locking lug into the locking recess 46. Thelower end Vplate 65 of the lug housing 66 may, if desired, be removableto permit ready access to and servicing or replace- -ment of the lockinglug 65 and its -actuating spring 67.

In accordance with an important aspect of the invention, the lockingfaces 65 and 46 of 4the locking lug 65 and the bolt 30 are both inclinedinwardly and rearwardly with respect to the line of movement of thebolt, to 'exert a forward wedging or camming force on the bolt incidentto the spring projection of the locking lug 65 into the recess 46. Whilethe locking faces are thus sufficiently inclined to transmit thisforward seating -or sealing force to the "bolt, the degree of angle ofinclination with respect to the line of movement of the bolt ismaintained generallynear, but somewhat less than, ninety degrees,

vor in other words within a range at which the frictionalinter-engagement between opposed faces 46', 65 will approximately equalthe retraction force exerted on or transmitted to the locking lugthrough the inter-engaged faces 46 and 65 'as an incident to rearwardgas pressures on 'the bolt.

In addition, the maintenance of but a slight camming angle is desirableas increasing the mechanical advantage which is obtainable by theinclined plane or wedging action between these faces and which tends toseat the bolt firmly in its sealing position incident to the springprojection of the locking lug into -therecess 46. lt has been found thata suitable angle of inclination for these faces 46' and 65 is in theneighborhood of fifteen degrees with respect to a plane which normallytransects the axis of the gun barrel and re-ceiver.

The locking 'lug spring 67 will be formed of sufficient strength t-oproject the locking lug into recess 47 with substantial force, wherebyto achieve the desired degree of seating force on the bolt. Such seatingforce will also serve to supplement the force of the bolt return spring32 in fully seating the various rounds of ammunition in the firingchamber 21, regardless of variati-ons in the proportions thereof withinreasonable tolerances.

It will be noted that the bolt lock or locking lug 65, when fully seatedin the locking recess 46, will normally be spaced somewhat Vfrom theblind inner end of the recess, thereby allowing space for further inwardmovement of the lug into Isaid recess as may be necessary to compensatefor wear on the locking and camming surfaces 46 and 65 as well as on thesealing surfaces 28 and 31 respectively, of the receiver and the =bolt.Thus there is achieved the important advantage of autom-atie wearcompensation on these respective surfaces.

It will be apparent that the weapon 'as thus far described, and evenwithout au-tomatic means for retraction of the locking lug 65, iscapable of operation as a single shot weapon. In order t-o achieve suchoperation it will be necessary to manually retract the locking lug or'bolt lock 65 to disengage it from the bolt 30 after each round is fred.It is then necessary to manually retract the bolt 30 by means of itshandle 35, to eject the expended cartridge 62 and to permit deliveryint-o the receiver in advance of the retracted bolt 39 of a fresh roundof ammunition P from the magazine 58. Release of the handle 35 will thenpermit the =bolt return spring 32 to project the bolt forwardly, movingthe fresh round of ammunition P in .advance thereof into the tiringchamber. The bolt lock 65 meanwhile, having been released, willautomatically be projected int-o the rec-ess 46 as 4the latter registerswith it. By inter-engagement between the inclined locking surfaces 65and 46', the bolt lock 65 will urge the bol-t 30 forwardly in-to itsbreech closing and sealing position.

The lock 65 is automatically retracted by engagement with the taperednose or sealing surface 31 of the bolt to permit the bolt to ride freelytherepast toward its forwardly projected sealing position. If desired,the locking lug 65 may be formed with a rearwardly directed inclined camsurface 69 for engagement by the tapered nose or sealing surface 31 ofthe bolt to facilitate this retraction action. Because of the constantspring pressure urging the locking lug 65 into the recess 46 and againstthe inclined locking surface 46', the lug will exert a constant andpositive forward wedging action on the bolt 30 even after the lug isfully projected into the recess 46.

The preferred means for facilitating manual retraction of the bolt lockor lug 65 is exemplified in the present rembodiment by the bolt releaserod 70 guided for longiing therein and is provided with a rearwardlypresented carnface 72 for camming engagement with the correspondinglyinclined cam face or surface 73 of the lock or lug 65. A spring 74coiled about the rod k70 under compression between the bearing 71 and asuitable stop 75 on the rod normally retains the rod withdrawn from thehousing 66 and disengaged from the bolt lock 65.

The rod 70 is adapted for manual actuation, either by direct grippingand forcing rearwardly of the rod, or by means of the bolt releaseplunger 76 slidably guided through a bearing 77 which in the presentinstance is afforded by the casing of the gas cylinder 78, hereinafterdescribed in more detail. The rear end of release plunger ,76 ispositioned and guided for abutting engagement with ward movement to therod 70. Normally the release plunger 76 is resiliently yieldablymaintained in its forwardly projected disengaged position by means ofthe compression spring 84B coiled about the plunger with its oppositeends abutting against the bearing 77 and the plunger. As thus arranged,the release plunger 76 is normally disengaged from the release rod 70 toavoid interference with actuation of the latter by automatic means, suchas hereinafter described.

For automatically disengaging the bolt lock or locking lug 65 from thebolt 30 in timed relation to the firing of a round of ammunition, thereis provided gas actuated automatic means exemplified by the piston 81disposed for longitudinal rearward movement in the cylinder 78 inresponse to pressurized gases which are admitted to the cylinder througha gas inlet passage 83 establishingr communication between the cylinderinterior and the interior of the barrel 20. The intake end of thepassage 83, through which it communicates with the barrel, is located ata suitable position along the length of the barrel and adjacent itsdischarge end to admit pressurized gases from rearwardly of theprojectile P as soon as the projectile shall have moved forwardly beyondthe inlet end of this passage.

In other words the position of the inlet end of the passage 83 is suchthat the piston 78 will be actuated to move the bolt release rod 70rearwardly to disengage the bolt lock or locking lug 65 from the bolt ata time when there is a sucient gas pressure remaining in the barrel toforce the expended cartridge case and bolt 62 and 30 respectively,rearwardly for achieving the several functions required for automaticfiring. Nevertheless the timing will be such that the retraction of thebolt is delayed until the gas pressures have been lowered beyond thedanger point.

In order that the operation of the release rod '7G may be achieved byeither the plunger 76 or the piston and cylinder unit 82, 78 withoutinterference with either by the other, the piston also is normallydisconnected from the release rod 70. To this end, the piston rod 84 isnormally detached from the bolt release rod 70, but in alignmenttherewith, and is adapted to return to its normal inoperative or idleposition at the end of each actuation by endwise pressure to the righttransmitted through the rod 70 from the plunger spring 74, as well as bythe pressure of gases or air trapped in the closed end of the cylinder.

It will thus be apparent that the release rod '70 exemplifies a suitablelinkage means interconnecting the piston and cylinder unit to the boltlock 65 for disengaging the latter from the bolt 30 on each actua-tingmovement of the piston, though obviously other specific forms of linkagemeans may be employed for the same purpose.

Operation Now to briefly summarize the overall operation of theinvention as an automatically tiring weapon, assuming that the weapon isto be brought into use for the first time, a loaded magazine 58 isoperatively connected with the receiver in the position shown in FIGURES1, 3 and 4. Assuming that Ithe firing chamber is empty, a round ofammunition may be moved from the magazine 58 into the ring chamber 21 bygrasping the bolt operating handle 35 and retracting the bolt rearwardly(after first releasing the bolt lock 65) to uncover the loading port 57.The sear 41 is retracted by successive engagement with the cam surface40 and 30 `respectively of the ring pin detent 4@ and bolt 3th to permitsuch retraction of the bolt. The uppermost round of ammunition from themagazine 58 will then be projected upwardly through said port 57 andinto the receiver 11 in front of the bolt 3i). Release of the boltoperating handle 35 will then permit return movement or forwardprojection of the bolt 30 under the pressure of its return spring 32. Asthe bolt moves forwardly it shoves the round of ammunition ahead of itinto the tiring chamber 62 and closes and seals the breech by sealingengagement of its tapered forward sealing surface 28 with the coactingconically tapered sealing surface 31 of the breech. As the bolt returnsforwardly past the sear 41 and bolt lock 65, these are successivelyretracted from its path by the tapered nose or sealing surface 31 of thebolt. When the bolt shall have moved forwardly beyond the scar 41, thelatter will have been immediately spring projected into the path ofmovement of the cocking detent or catch 40 of the ring pin to cock thering pin 37 against its spring 38. As the bolt approaches its sea-ted orbreech sealing position and its locking recess 46 moves abreast of thebolt lock or lug 65, the latter, after having been depressed by cammingengagement with the tapered nose or sealing surface 31 of the bolt willthen be strongly projected by its spring 67 into the locking Yrecess 46.The ensuing locking and wedging engagement between-the inclined lockingsurfaces 46 and 65 will then exert a strong forward thrust on the boltto supplement its sealing engagement with the tapered sealing surface 31and to assist the bolt return spring 32, if necessary in completing themovement of the ammunition into the ring chamber.

The bolt lock spring 6/ `will then continue to transmit a constantseating or sealing thrust to the bolt by way of the inter-engagedwedging surfaces 65 and 46 to maintain the bolt sealed and rmly lockedin its forwardly projected position during ring of the round ofammunition then within the firing chamber.

At this time the weapon will have been loaded and cocked in readinessfor automatic tiring which may be achieved in customary manner simply byrepeated pulling of the trigger 47 whenever desired.

As the trigger is pulled to re the rst round, the ensuing downwardmovement of lits forwardly projecting lever arm 52 in engagement withthe sear actuating lug 55 will disengage the scar from the tiring pin3'7 so that the ensuing forward projection of the latter by its spring39 will cause the striker 38 to impact against the primer 63 of thebooster cartridge 62. The ensuing ignition of the booster cartridge and,through it, of the propellant charge within the projectile P, will serveto fire the missile projectile P from the barrel 20.

As the missile or projectile P moves forward sufficiently to uncover thegas release ports 25, the escape of gases through these ports will serveto maintain the gas pressure Within the barrel 20 within safe limits.The gases thus released will be discharged forwardly through the releasepassage 27 for discharge forwardly in the form of a sheath of gasessurrounding the rearwardly directed blast of propellant gases ejectedfrom the missile as the latter emerges from the gun barrel Ztl?. Thusthe gases released through the passage 27, in addition to reducing thepressure within the barrel, will serve the added function of projectingor shielding the gunner from the rearwardly directed blast of the rocketprojectile.

J ust before the projectile arrives at the end of the barrel it movespast the inlet end of the gas cylinder inlet passage 33 to permit thepressurized gases behind it to i'low into the cylinder 7S and urge thepiston 82, its piston rod 84 and the bolt release rod '70 toward theleft to Withdraw or disengage :the bolt lock 65 from the bolt.Immediately pursuant to such disengagement, the residual gas pressurewithin the barrel will force the unlocked bolt 30, as well as the emptycartridge 62 to the left or toward the retracted position of the bolt.In the resulting retraction and return of the bolt, the weapon will bereloaded and cocked, in readiness for iiring a further round, in thesame manner above described.

Even though the trigger 46 may not yet have been released subsequent tothe firing of the preceding round, it will have been disengaged from thescar to permit the latter to re-enter the receiver in position forengaging and cocking the firing pin during the last stages of theforward movement of the bolt. Release of the trigger will then causeupward swinging movement of its lever arm 52, while the ensuing cammingengagement of cam surface 55 with the disconnector 54 will have causedthe latter to be retracted for movement upwardly past the lug 55 to bethereafter spring projected to a position overlying and abutting theupper face of such lug to re-establish the operative connection betweenthe trigger and sear prior to the next firing.

The weapon may then be fired automatically by repeatedly pulling thetrigger 46 until the contents of the magazine 58 are exhausted, at whichtime the magazine may be refilled and the weapon reloaded in the mannerearlier described.

Where it is desired to fire the weapon as a single sho-t weapon, thismay be achieved simply by omitting the magazine and by feedingammunition manually thro-ugh the loading port -57 in advance of thebolt, it being understood that the latter will have had its lock 72manually retracted in the manner earlier described following which thebolt itself will have been retracted and maintained in retractedposition during such insertion of ea-ch new round of ammunition. Releaseof the bolt operating handle 3'5 will then permit return of the bolt toits forwardly projected sealing position to load and cock the weapon inreadiness for firing.

Having thus described my invention, I claim:

1. In an automatically ring closed breech rocket gun, comprising areceiver and a barrel communicating with each other through a breechopening, said receiver defining a sealing surface around said breechopening, a bolt guided for projection and retraction movement in saidreceiver toward and away from said breech opening respectively andformed with a sealing surface for flush sealing engagement with saidsealing surface of the receiver in the forwardly projected position ofthe bolt, a bolt lock slidably guided in said receiver for movementtransversely to the bolt movement into and from locking engagement withthe bolt in the forwardly projected position of the latter, a firing pinguided in the bolt for movement parallel to the bolt movement, springmeans associated with the firing pin for normally projecting the sameforwardly, and sear mechanism carried by the receiver for releasablyretaining said spring means in a retracted cocked position in readinesswhen released to project said firing pin into operative engagement withthe primer of a round of ammunition in said barrel, the improvementcomprising a gas piston and cylinder unit communicating with said barrelfor the reception of pressurized gas therefrom for actuating the saidunit, linkage means operatively interconnecting the said piston andcylinder unit to the bolt lock to retract the latter from lockingengagement with the bolt incident to the tiring of said round throughsaid barrel to permit recoil movement of the bolt from its saidprojected position to a retracted position, means for then resilientlyreturning said bolt to its said projected position and means operativein response to each such return movement of the bolt for projecting saidbolt lock into operative locking engagement with the bolt.

2. An automatically firing closed breech rocket gun as defined in claim1, in which said linkage means includes a rod guided on said gun forlongitudinal movement between said bolt lock and the piston of saidpiston and cylinder unit, said bolt lock having an inclined cam surfacedirectly operatively engaged by the rear end of said rod to disengagesaid bolt lock from the bolt incident to longitudinal movement of thebolt rod in a given direction, and spring means connected with said rodfor urging said rod in a direction opposite to said given direction.

3. An automatically firing closed breech rocket gun as defined in claim2 including a manually controllable release plunger carried by said gunfor longitudinal movement into endwise thrusting abutment with saidrelease rod in said given direction, a releasable connection betweensaid rod and the piston, including a piston rod fixed to the piston andhaving a free end extending in said direction for abutting endwiseengagement with said release rod, whereby said piston may be actuatedindependently of the release plunger to disengage the bolt lock.

4. An automatically firing closed breech rocket gun as defined in claim1, in which said bolt and said bolt lock have relatively opposed lockingfaces extending generally transversely to the bolt movement, butslightly inclined with respect to a plane normal to said bolt movementto transmit the projecting force on said bolt lock into a forceconstantly urging said bolt toward its projected position, said boltbeing formed with a locking recess for locking reception of the boltlock, said locking face of the bolt lock being defined by a rearwardlypresented face of said recess.

5. An automatically firing closed breech rocket gun as defined in claim4, in which the locking faces of the bolt and bolt lock respectively arearranged to arrest the projection movement of the bolt lock in aposition wherein the latter is spaced from the bottom of the lockingrecess, whereby to permit an increased extent of such projectionmovement to occur for the purpose of automatically compensating for wearon said locking faces and on said sealing surfaces of the bolt andreceiver respectively.

6. An automatically firing closed breech rocket gun as `defined in claim5, in which said sear is of greater width than said locking recesswhereby to ride freely over the latter in order to avoid interferencewith movement of the bolt.

7. In an automatically firing closed breech rocket gun, the combinationcomprising a receiver having a hollow interior communicating with therearwardly opening firing chamber of the gun, a bolt disposed in saidreceiver for sliding movement between a retracted position away fromsaid firing chamber and a forwardly projected position in sealing -gasrelation with respect to said tiring chamber, a gun barrel extendingforwardly from said firing chamber, a bolt lock guided on said receiverfor movement transversely to the movement of the bolt into and from aprojected operative bolt locking position partially across the path ofmovement of lsaid bolt movement, said bolt and said bolt lockrespectively having rearwardly and forwardly presented locking faces forabutting locking engagement in the projected operative positions of bothsaid bolt and said bolt lock, a gas cylinder and piston unit carried bysaid gun, with the said unit in communication with the interior of saidbarrel for the reception therefrom of actuating gas pressure created byeach firing of said gun, mechanism operatively connecting said unit tothe said bolt lock to retract the latter incident to such actuating gaspressure, whereby to permit longitudinal sliding movement of the bolt toits said retracted position, resilient means for returning said bolt toits forwardly projected position after each firing, and meansautomatically operative on each such return of the bolt to its forwardlyprojected position for urging said bolt lock into its operative lockingposition with respect to said bolt.

8. In an automatically firing closed breech rocket gun including areceiver and a bolt guided for movement to and from breech closingposition therein, the combination including a bolt lock guided on saidreceiver for movement into and from a locking recess in said bolt, saidrecess being positioned for reception of said bolt lock in the breechclosing position of the bolt, and spring means associated with said boltlock for urging it into said recess, a firing pin guided for operativemovement through said bolt, a sear guided on the receiver for projectioninto operative position for engagement with the firing pin to cock thelatter incident to forward movement of the bolt toward its breechclosing position, resilient means normally urging said sear intooperative position, cooperating cam means on the said firing pin andbolt for thrusting the sear to a retracted inoperative position incidentto rearward movement therepast of the bolt and the firing pin, said bolthaving a tapered nose for operative engagement with the Sear and withthe said bolt lock incident to forward projection of the bolt toward itssealing position to urge the sear and the bolt lock successively toretracted positions.

9. The combination dened in claim 8, wherein said receiver is providedwith a magazine which communicates with the interior of the receiverthrough a loading port normally abreast of and blocked by the bolt inthe breech sealing position of the bolt, said sear and Said bolt lockbeing disposed rearwardly and forwardly respective of said magazine,said receiver being formed with an ejector port located rearwardly ofsaid loading port, and said bolt being disposed for movement from itsforwardly projected breech sealing position to a rearwardly retractedposition beyond said ejection port.

References Cited by the Examiner UNITED STATES PATENTS BENJAMN A.BORCHELT, Primary Examiner.

FRED C. MATTERN, JR., Examiner.

1. IN AN AUTOMATICALLY FIRING CLOSED BREECH ROCKET GUN, COMPRISING ARECEIVER AND A BARREL COMMUNICATING WITH EACH OTHER THROUGH A BREECHOPENING, SAID RECEIVER DEFINING A SEALING SURFACE AROUND SAID BREECHOPENING, A BOLT GUIDED FOR PROJECTION AND RETRACTION MOVEMENT IN SAIDRECEIVER TOWARD AND AWAY FROM SAID BREECH OPENING RESPECTIVELY ANDFORMED WITH SAID SEALING SURFACE FOR FLUSH SEALING ENGAGEMENT WITH SAIDSEALING SURFACE OF THE RECEIVER IN THE FORWARDLY PROJECTED POSITION OFTHE BOLT, A BOLT LOCK SLIDABLY GUIDED IN SAID RECEIVER FOR MOVEMENTTRANSVERSELY TO THE BOLT MOVEMENT INTO AND FROM LOCKING ENGAGEMENT WITHTHE BOLT IN THE FORWARDLY PROJECTED POSITION OF THE LATTER, A FIRING PINGUIDED IN THE BOLT FOR MOVEMENT PARALLEL TO THE BOLT MOVEMENT, SPRINGMEANS ASSOCIATED WITH THE FIRING PIN FOR NORMALLY PROJECTING THE SAMEFORWARDLY, AND SEAR MECHANISM CARRIED BY THE RECEIVER FOR RELEASABLYRETAINING SAID SPRING MEANS IN A RETRACTED COCKED POSITION IN READINESSWHEN RELEASED TO PROJECT SAID FIRING PIN INTO OPERATIVE ENGAGEMENT WITHTHE PRIMER OF A ROUND OF AMMUNITION IN SAID BARREL, THE IMPROVEMENTCOMPRISING A GAS PISTON AND CYLINDER UNIT COMMUNICATING WITH SAID BARRELFOR THE RECEPTION OF PRESSURIZED GAS THEREFROM FOR ACTUATING THE SAIDUNIT, LINKAGE MEANS OPERATIVE LY INTERCONNECTING THE SAID PISTON ANDCYLINDER UNIT TO THE BOLT LOCK TO RETRACT THE LATTER FROM LOCKINGENGAGEMENT WITH THE BOLT INCIDENT TO THE FIRING OF SAID ROUND THROUGHSAID BARREL TO PERMIT RECOIL MOVEMENT OF THE BOLT FROM ITS SAIDPROJECTED POSITION TO A RETRACTED POSITION, MEANS FOR THEN RESILIENTLYRETURNING SAID BOLT TO ITS SAID PROJECTED POSITION AND MEANS OPERATIVEIN RESPONSE TO EACH SUCH RETURN MOVEMENT OF THE BOLT FOR PROJECTING SAIDBOLT LOCK INTO OPERATIVE LOCKING ENGAGEMENT WITH THE BOLT.